A mobility management entity (MME) is a key control node in a Long Term Evolution (LTE) network. The mobility management entity is responsible for managing and storing a user equipment (UE) context, allocating a temporary identity to the UE, authenticating the UE, processing all non-access stratum messages between the mobility management entity and the UE, and the like.
In the LTE network, the UE needs to send an authentication request, a service request, or the like to the MME by using an evolved NodeB (eNB), and the eNB needs to transfer a message by using an S1 interface established between the eNB and the MME. The S1 interface is a logical interface, and is a communications interface between the eNB and the MME. With the development of an LTE network system, more MMEs may be needed to run simultaneously to meet a requirement of the system. Therefore, a quantity of S1 interfaces established between the eNB and the MME in the system and a quantity of other interfaces increase greatly, which increases complexity of the network system. In addition, increase in the quantity of MMEs will inevitably cause consumption of considerable resources.